System of distribution.



a constant-current transformer and a source UNITED STATES PATENT Onricn,

ELIHU THOMSON, OF'SWAMPSOOTT, MASSACHUSETTS, ASSIGNOR TO'THE GENERALELECTRIC COMPANY, OF NEW YORK.

SYSTEM OF DISTRIBUTION.

SPECIFICATION formingpart of Letters Patent No. 654,367, dated July 24,1900.

Original application filed September 10, 18 97,-Serial No. 651,212.Divided and this application filed May 18,1899. Serial No. 717,261. (Nomodel.)

To all whom it ntcry concern:

Be it known that I, ELIHU THOMSON, a citizen of the United States,residing at Swampscott, county of Essex, State of Massachusetts, haveinvented certain new and useful Improvements in Systems of Distribution,(Case No. 1,276,) of which the following is a specification.

This application is a division of my former application, Serial No.651,212, filed September 10, 1897. My former application, generallyspeaking, relates to circuits fed by a combination of constant-currentand constantpotential transformers. The claims of the presentapplication are more generic in character and cover a circuit fedconjointly from of constant electromotive force which may or may notconsist of aconstant-potential-transformer secondary. As regards thisfeature, the present application is to be regarded as the broad case andis not to be considered as limited to the precise apparatus shown forpurposes of illustration.

In supplying a circuit from the secondary of a constant-currenttransformer and from a source of constant electromotive force severalimportant results are obtained. The regulating action of theconstant-current transformer acts to maintain a constant current in thecircuit, and this action takes place so long as the load on the circuitis such as to require an electromotive force greater than thatrepresented by the source of constant electromotive force. Under thesecircumstances' the load on the circuit can never be reduced to zero, butonly to a minimum represented by the electromotive force of theconstant-potential source. This condition of affairs is, however, nosubstantial disadvantage in practice. By employing this method offeeding a constant-current circuit a much higher power factor isobtained than would be the'case if the total 'electromotive force werederived from the secondary of a constant-current transformer, of a sizelarge enough to generate the additional electromotive force whichaccording to my invention is supplied from a constant-potential source.A constant-current transformer of such increased capacity seriouslyreduces the power factor of the line when operating at light loads,while according to my invention the constant-current transformeremployed does not begin to reduce the power factor of the line to anyappreciable extent until the electromotive force in circuit is greaterthan that of the constant-potential source. I

My invention will be more clearly apprehended by reference to theaccompanying drawing, while its scope will be indicated in the claimsappended hereto.

In the drawing, Z and Z represent constant-potential alternating-currentmains fed from any suitable source of energy. The primary P of theconstant-current transformer T is connected directly across these mains,while its secondary (indicated at S) is included in series with aseparate circuit the leads of which a h are also connected across thesupply-mains Z Z The circuit a b is arranged to supply translatingdevices in se-' ries, and in the drawing I have for purposes ofillustration shown these devices as transformers into the secondaries ofwhich are connected other translating devices-such as incandescentlamps, arc-lights, or the like. It is obvious, however, that instead ofthese transformers in the circuit a and b any other form of translatingdevice may be employed. The transformers of the circuit a and b areindicated at P to P while their secondaries are shown, respectively, atS to S These transformer-secondaries may supply translating devicesarranged either in series or in parallel, as may be desired. Thesecondary S is shown as supplying lamps in parallel to each other, whilethe other secondaries S to S supply lamps or other translating devicesin series.

Film cut-outs F or other safety devices may be provided in connectionwith the primaries or secondaries of the transformers in or der toprotect the line in case of accidental opening of any of thesubcircuits. In case of accidental rupture of a subcircuit the film.

cut-out will be punctured, if properly pro portioned, and thus act as ashunt, so as to permit the Working of the remaining load.

'hat I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. The combination with constant-potential mains, of a circuit connectedacross the same and including in series therewith the secondary of aconstant-current transformer the primary of which is also connectedacross the said mains.

2. The combination with constant-potential mains, of translating devicesin a circuit across said mains, and a constantcurrent transformer withits secondary in said circuit and its primary connected across saidmains.

3. The combination of a circuit fed from a source of constantelectromotive force and a device in said circuit fed also from saidsource giving rise to an electromotive force which varies inversely withthe current in the circuit.

it. The combination of a circuit fed from a source of constantelectromotive force and a device in said circuit fed also from saidsource giving rise to an electromotive force which automatically variesinversely With the current in the circuit.

5. In a series system of distribution, the combination of a seriescircuit including therein a plurality of transformer-windings, and filmcut-outs arranged in shunt to said windings.

6. In a series system of distribution, the combination of a circuitincluding therein a plurality of translating devices, film cut-outs inshunt to said translating devices and means for causing a constantcurrent to flow in said circuit.

In Witness whereof I have hereunto set my hand this 15th day of May,1899.

ELIIIU THOMSON.

\Vitnesses:

DUGALD MoKlnLor, HENRY O. TESTENDARP.

